当具有活动事件处理程序的线程退出时会发生什么？ [英] What happens when a thread with active event handler exits ?

问题描述

如果它直接退出，如何让线程等待事件处理程序完成。



我尝试过：



尝试通过睡眠阻止线程的不同方法，等待退出等......但似乎没有什么是正确的方法。

if it directly exits, how to make a thread wait for event handler to finish.

What I have tried:

tried diferent ways to block thread by sleeping, wait for exit etc... but nothing seemed to be the right way.

推荐答案

您必须使用事件等待句柄对象。你不应该做睡眠，任何旋转等待，没有这样的。如果你等待某个对象，你的线程将进入等待状态：它被关闭并且没有被调度回执行，直到它被唤醒，在等待状态下花费零CPU时间。你也可以等一个帖子。



请看我过去的答案：

暂停正在运行的线程 [ ^ ]，

在webservice中运行一个永远不会终止的作业/线程/进程（asp.net） [ ^ ]，
使代码线程安全 [ ^ ]，

Thread中的ManualResetEvent和AutoResetEvent [ ^ ]。



等待一些线程完成，也处于等待状态，你可以使用 System.Threading.Thread.Join ：

Tread.Join Method（System.Threading） [ ^ ] 。

-SA

You have to use an event wait handle object. No way you should do Sleep, any spin wait, nothing like that. If you wait for some object, your thread goes to a wait state: it is switched off and not scheduled back to execution until it is waken up, spending zero CPU time in wait state. You can also wait for a thread.

Please see my past answers:
pause running thread[^],
Running exactly one job/thread/process in webservice that will never get terminated (asp.net)[^],
Making Code Thread Safe[^],
ManualResetEvent and AutoResetEvent in Thread[^].

To wait for some thread to finish, also in a wait state, you can use System.Threading.Thread.Join:
Thread.Join Method (System.Threading)[^].

—SA

我觉得使用相对较新的 async C＃的功能是实现异步方法的最佳方法，因为它在完成时为方法提供了一个退出点。您可以像这样使用它

I feel that using the relatively new async feature of C# is the best way to implement asynchronous methods because it provides an exit point for the method when it completes. You can use it like this

//subscribe to the event
button.Click += MyEventHandlerAsync;
// When the event fires this handler is called
private async void MyEventHandlerAsync(object sender, RoutedEventArgs e)
       {
           //the UI  thread starts the task here and then returns
           //the task runs on the threadpool
           string text = await Task.Run(() => this.MyMethodThatReturnsAString());
           //When the task finishes, control returns here
           //Do something with the result
           //Set a label on the UI thread
           this.label.Content = text;
       }

       private string MyMethodThatReturnsAString()
       {
           //Long running method that finds the meaning of life
           //........
           return "Forty Two ";
       }

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